1. Field of the Invention
The present invention relates generally to a cleaning system for a telephone number list. More specifically, the invention relates to a cleaning system for a telephone number list in a customer list and so forth to be used in tele-marketing and so forth, for deleting null telephone numbers from the telephone number list.
2. Description of the Related Art
In various businesses utilizing telephone, a telephone number list is quite important information and thus has to be maintained for deleting telephone numbers which become unnecessary or are found null from the list to keep reasonable reliability and whereby to prevent degradation of the value of the contained information. The customer information in such list naturally contains variable information. One of such variable information is the telephone number. Namely, the telephone number of the customer may be varied due to termination of use of the registered telephone number, changing to other telephone number, and can be null as originally registered. Such telephone numbers, through which customers cannot be reached, will be generally referred to as "null telephone number" throughout the disclosure and appended claims. In order to keep reasonable reliability of the list, such null telephone numbers has to be deleted from the list or to be replaced with correct or new telephone numbers.
Conventionally, maintenance of the list has been performed upon giving a phone call to respective customers according to the telephone number list in certain businesses. Namely, deletion or updating of the null telephone numbers has been done with verifying response from respective customers.
The conventional telephone number list cleaning method for deleting and updating the list associating with business inherently cause significant waste and absurdity or irrationality in certain type of businesses. Namely,performing business to the customers having null telephone numbers which should be deleted from the list, wasteful expense should be incur to cause a trouble on people who are not customers. On the other hand, for the customers who has moved, it is possible to redundantly perform businesses to the old telephone number and the new telephone to cause waste both in time and cost.